In the growing of agricultural and horticultural crops, treatment of same by spraying, for example to protect the crop against pests and diseases, is now an important part of the crop growing program.
However, conventional field spraying equipment is subject to significant shortcomings due to the fact that the spray only reaches the portion of the foliage directly in the path of the spray. Thus, where a crop has dense foliage, as in the case of a potato crop, the applied spray does not reach the lower leaves beneath the top leaf cover. As potato crops are highly susceptible to fungal attack, this inability to properly spray the crop is of considerable significance.
There is disclosed in U.S. Pat. No. 1,348,038 to Neumeyer a sprayer for plants in which spaced downwardly extending pipes 16 are fixed to a transverse pipe 14 and deliver liquid to nozzles which are usually directed upwardly to deliver spray onto vines from below and upwardly. There is a similar disclosure in CH 229,146 (Leuenberger). Both these prior specifications show the use of fixed droplegs or the like for spraying between crop rows in a generally upwardly-directed direction, and are subject to the shortcoming that, in use, the droplegs vary in their proximity to the crop rows and in the case of established crops may cause significant damage.
In FR 2,563,970 (Balligand) there is disclosed a shredding/spraying implement in which individual units are biased laterally outwards in one particular direction against the crop rows in order to follow their irregular profile by actual contact with the crop stalks. Such a proposal is unacceptable for a machine intended to minimize crop contact and damage.